US5986305A - Semiconductor device with an inverse-T gate lightly-doped drain structure - Google Patents

Semiconductor device with an inverse-T gate lightly-doped drain structure Download PDF

Info

Publication number
US5986305A
US5986305A US09/050,669 US5066998A US5986305A US 5986305 A US5986305 A US 5986305A US 5066998 A US5066998 A US 5066998A US 5986305 A US5986305 A US 5986305A
Authority
US
United States
Prior art keywords
region
inverse
semiconductor substrate
top surface
shaped silicon
Prior art date
Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
Expired - Lifetime
Application number
US09/050,669
Inventor
Shye-Lin Wu
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Taiwan Semiconductor Manufacturing Co TSMC Ltd
Texas Instruments Acer Inc
Original Assignee
Texas Instruments Acer Inc
Priority date (The priority date is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the date listed.)
Filing date
Publication date
Application filed by Texas Instruments Acer Inc filed Critical Texas Instruments Acer Inc
Priority to US09/050,669 priority Critical patent/US5986305A/en
Assigned to TEXAS INSTRUMENTS-ACER INCORPORATED reassignment TEXAS INSTRUMENTS-ACER INCORPORATED ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: WU, SHYE-LIN
Application granted granted Critical
Publication of US5986305A publication Critical patent/US5986305A/en
Assigned to TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD. reassignment TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: TSMC-ACER SEMICONDUCTOR MANUFACTURING CORPORATION
Assigned to TSMC-ACER SEMICONDUCTOR MANUFACTURING CORPORATION reassignment TSMC-ACER SEMICONDUCTOR MANUFACTURING CORPORATION ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: ACER SEMICONDUCTOR MANUFACTURING INC.
Anticipated expiration legal-status Critical
Expired - Lifetime legal-status Critical Current

Links

Images

Classifications

    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66477Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66568Lateral single gate silicon transistors
    • H01L29/66575Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate
    • H01L29/6659Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
    • H01L29/66598Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET forming drain [D] and lightly doped drain [LDD] simultaneously, e.g. using implantation through the wings a T-shaped layer, or through a specially shaped layer
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/40Electrodes ; Multistep manufacturing processes therefor
    • H01L29/41Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions
    • H01L29/423Electrodes ; Multistep manufacturing processes therefor characterised by their shape, relative sizes or dispositions not carrying the current to be rectified, amplified or switched
    • H01L29/42312Gate electrodes for field effect devices
    • H01L29/42316Gate electrodes for field effect devices for field-effect transistors
    • H01L29/4232Gate electrodes for field effect devices for field-effect transistors with insulated gate
    • H01L29/42372Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out
    • H01L29/42376Gate electrodes for field effect devices for field-effect transistors with insulated gate characterised by the conducting layer, e.g. the length, the sectional shape or the lay-out characterised by the length or the sectional shape
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66477Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/665Unipolar field-effect transistors with an insulated gate, i.e. MISFET using self aligned silicidation, i.e. salicide
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66477Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66568Lateral single gate silicon transistors
    • H01L29/66575Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate
    • H01L29/6659Lateral single gate silicon transistors where the source and drain or source and drain extensions are self-aligned to the sides of the gate with both lightly doped source and drain extensions and source and drain self-aligned to the sides of the gate, e.g. lightly doped drain [LDD] MOSFET, double diffused drain [DDD] MOSFET
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66477Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66568Lateral single gate silicon transistors
    • H01L29/66651Lateral single gate silicon transistors with a single crystalline channel formed on the silicon substrate after insulating device isolation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26Bombardment with radiation
    • H01L21/263Bombardment with radiation with high-energy radiation
    • H01L21/265Bombardment with radiation with high-energy radiation producing ion implantation
    • H01L21/26506Bombardment with radiation with high-energy radiation producing ion implantation in group IV semiconductors
    • H01L21/26513Bombardment with radiation with high-energy radiation producing ion implantation in group IV semiconductors of electrically active species
    • H01L21/2652Through-implantation
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L21/00Processes or apparatus adapted for the manufacture or treatment of semiconductor or solid state devices or of parts thereof
    • H01L21/02Manufacture or treatment of semiconductor devices or of parts thereof
    • H01L21/04Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer
    • H01L21/18Manufacture or treatment of semiconductor devices or of parts thereof the devices having at least one potential-jump barrier or surface barrier, e.g. PN junction, depletion layer or carrier concentration layer the devices having semiconductor bodies comprising elements of Group IV of the Periodic System or AIIIBV compounds with or without impurities, e.g. doping materials
    • H01L21/26Bombardment with radiation
    • H01L21/263Bombardment with radiation with high-energy radiation
    • H01L21/265Bombardment with radiation with high-energy radiation producing ion implantation
    • H01L21/266Bombardment with radiation with high-energy radiation producing ion implantation using masks
    • HELECTRICITY
    • H01ELECTRIC ELEMENTS
    • H01LSEMICONDUCTOR DEVICES NOT COVERED BY CLASS H10
    • H01L29/00Semiconductor devices adapted for rectifying, amplifying, oscillating or switching, or capacitors or resistors with at least one potential-jump barrier or surface barrier, e.g. PN junction depletion layer or carrier concentration layer; Details of semiconductor bodies or of electrodes thereof  ; Multistep manufacturing processes therefor
    • H01L29/66Types of semiconductor device ; Multistep manufacturing processes therefor
    • H01L29/66007Multistep manufacturing processes
    • H01L29/66075Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials
    • H01L29/66227Multistep manufacturing processes of devices having semiconductor bodies comprising group 14 or group 13/15 materials the devices being controllable only by the electric current supplied or the electric potential applied, to an electrode which does not carry the current to be rectified, amplified or switched, e.g. three-terminal devices
    • H01L29/66409Unipolar field-effect transistors
    • H01L29/66477Unipolar field-effect transistors with an insulated gate, i.e. MISFET
    • H01L29/66545Unipolar field-effect transistors with an insulated gate, i.e. MISFET using a dummy, i.e. replacement gate in a process wherein at least a part of the final gate is self aligned to the dummy gate
    • YGENERAL TAGGING OF NEW TECHNOLOGICAL DEVELOPMENTS; GENERAL TAGGING OF CROSS-SECTIONAL TECHNOLOGIES SPANNING OVER SEVERAL SECTIONS OF THE IPC; TECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10TECHNICAL SUBJECTS COVERED BY FORMER USPC
    • Y10STECHNICAL SUBJECTS COVERED BY FORMER USPC CROSS-REFERENCE ART COLLECTIONS [XRACs] AND DIGESTS
    • Y10S257/00Active solid-state devices, e.g. transistors, solid-state diodes
    • Y10S257/90MOSFET type gate sidewall insulating spacer

Definitions

  • the present invention relates to a semiconductor transistor, and particularly, to an ultra-short channel metal-oxide-semiconductor field effect transistor (MOSFET) with an inverse-T gate lightly-doped drain (ITLDD) structure.
  • MOSFET metal-oxide-semiconductor field effect transistor
  • ILDD inverse-T gate lightly-doped drain
  • MOS Metal-oxide-semiconductor
  • DRAMs giga-bit dynamic random access memories
  • a device design window of process conditions such as oxide thickness, punch-through doses, and lightly-doped drain (LDD) doses is disclosed in Hyunsang Hwang et al., "Performance and Reliability Optimization of Ultra Short Channel CMOS Device for Giga-bit DRAM Applications," IEEE IEDM Tech. Dig., pages 435-438 (1995) which is hereby incorporated by reference.
  • LDD lightly-doped drain
  • ITLDD inverse-T lightly-doped drain
  • an ultra-short channel MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure includes a semiconductor substrate, which includes a top surface; and a source region formed in the semiconductor substrate. Further, a drain region is formed in the semiconductor substrate spaced from the source region by a channel region. The drain region comprises a first doped portion adjacent the channel region and abutting to the top surface of the semiconductor substrate; and a second doped portion spaced from the channel region by the first doped portion and abutting to the top surface of the semiconductor substrate.
  • the present invention includes a first silicon oxide layer formed on the semiconductor substrate, the first silicon oxide layer being disposed over the channel region; and an inverse-T shaped silicon region formed on the first silicon oxide layer, wherein the inverse-T shaped silicon region is approximately disposed within the area of the first silicon oxide layer.
  • a second silicon oxide sidewall insulating region abutting to a sidewall of the inverse-T shaped silicon region is provided, and a first silicide region is formed on the top surface of the inverse-T shaped silicon region.
  • a second silicide region is formed on the top surface of the source region, and a third silicide region is formed on the top surface of the drain region.
  • FIGS. 1-11 show cross-sectional views illustrative of various stages in the fabrication of an ultra-short channel MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure in accordance with the present invention.
  • ILDD inverse-T gate lightly-doped drain
  • FIG. 1 shows a cross-sectional view illustrative of a portion of a semiconductor substrate 10 having field oxide regions 11 thereon in accordance with one embodiment of the present invention, wherein a thin gate oxide layer 12 having thickness of about 15-150 angstroms is grown on the substrate 10, for example, in a conventional thermal furnace.
  • a polysilicon layer 14 such as an undoped polysilicon layer, amorphous silicon layer or stacked silicon layers, is deposited on the gate oxide layer 12, and is used for forming a portion of a gate structure, which will become clear after the embodiment is described in details.
  • this polysilicon layer 14 is preferably deposited using a conventional low pressure chemical vapor deposition (LPCVD).
  • LPCVD low pressure chemical vapor deposition
  • a dielectric cap layer 16 such as a silicon nitride layer, is formed over the polysilicon layer 14 to a thickness of about 100 to 1000 angstroms.
  • the silicon nitride layer 16 is deposited using a conventional low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD).
  • LPCVD low pressure chemical vapor deposition
  • PECVD plasma enhanced chemical vapor deposition
  • a sacrificial semiconductor layer 18 is formed on the silicon nitride layer 16.
  • n+ doped polysilicon is preferably chosen as the material of this sacrificial layer 18, and is deposited using a standard chemical vapor deposition process to a thickness of about 500-3000 angstroms.
  • a photoresist layer 20 is then formed and patterned on the doped polysilicon layer 18 using conventional photolithography techniques, thereby defining a gate region in the doped polysilicon layer 18 after the doped polysilicon layer 18 is etched back as shown in FIG. 2.
  • the patterned doped polysilicon layer 18 is then subjected to, for example, a low temperature (about 700-950° C.) steam oxidation process to oxidize the doped polysilicon layer 18, forming thermal polyoxide layer 22 into the doped polysilicon layer 18 along the sidewalls and top surface of the doped polysilicon layer 18 as shown in FIG. 3.
  • a low temperature about 700-950° C.
  • the silicon nitride layer 16 is etched, and the undoped polysilicon layer 14 is partially etched, forming a cross section as shown in FIG. 4.
  • the thermal polyoxide layer 22 is then removed, for example, by diluted hydrofluoric (HF) solution or buffered oxide etch (BOE), wherein the remained undoped polysilicon layer 14 is used to protect the field oxide regions 11 and the gate oxide layer 12 from being effected.
  • the silicon nitride layer 16 is etched using the doped polysilicon layer 18 as a mask, resulting in the cross section shown in FIG. 5.
  • the formed silicon nitride layer 16 is further used as a mask to etch the undoped polysilicon layer 14, resulting in an inverse-T gate structure as shown in FIG. 6.
  • the substrate 10 is then subjected to an ion implantation through the inverse-T gate structure, forming source/drain region 9 having a lightly-doped drain profile in the substrate 10 as shown in FIG. 7.
  • a spacer 24 is formed on the sidewalls of the silicon nitride layer 16, the undoped polysilicon layer 14, and the gate oxide layer 12.
  • silicon oxide is chosen as the material of the spacer 24.
  • This oxide spacer 24 is preferably formed by firstly blanket depositing a silicon oxide layer 24 by a chemical vapor deposition (CVD) over the structure of FIG. 7, followed by etching back this silicon oxide layer 24.
  • CVD chemical vapor deposition
  • CVD chemical vapor deposition
  • the gate region in the undoped polysilicon layer 14, and the source/drain region 9 in the substrate 10 are then doped by a high dose (about 10 14 -10 16 atoms/cm 2 ) implant through the metal layer 26.
  • an annealing process is performed to form silicide regions 28 over the gate region 14 and source/drain region 9, therefore forming an ultra-short channel salicided MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure as shown in FIG. 11.
  • the annealing process is preferably a conventional two-step rapid thermal process (RTP).
  • RTP rapid thermal process
  • the oxide spacer 24 previously formed in connection with FIG. 8 is used in the resultant MOSFET structure to prevent the silicide region 28 on the gate 14 from being electrically bridged to the silicide region 28 on the source/drain 9.
  • the term "ultra-short" in this specification is commonly used in semiconductor industry to refer to a channel width in the range of about 4-100 nm.

Abstract

An ultra-short channel device with an inverse-T gate lightly-doped drain (ITLDD) structure is disclosed. The present invention includes a semiconductor substrate, which includes a top surface; a source region formed in the semiconductor substrate; and a drain region formed in the semiconductor substrate spaced from the source region by a channel region. Further, the present invention also includes an inverse-T shaped silicon region formed over the semiconductor substrate, wherein the inverse-T shaped silicon region is approximately disposed within the area of the channel region; and a sidewall insulating region abutting to a sidewall of the inverse-T shaped silicon region. A first conductive region is formed on the top surface of the inverse-T shaped silicon region, and a second conductive region is formed on the top surface of the source region. Also, a third conductive region is formed on the top surface of the drain region.

Description

BACKGROUND OF THE INVENTION
1. Field of the Invention
The present invention relates to a semiconductor transistor, and particularly, to an ultra-short channel metal-oxide-semiconductor field effect transistor (MOSFET) with an inverse-T gate lightly-doped drain (ITLDD) structure.
2. Description of the Prior Art
Metal-oxide-semiconductor (MOS) devices with ultra-short (less than 0.1 μm) channel are required for high frequency operation, for example, in a high-speed ring oscillator. The major constrains for 0.1 μm (or less) gate length metal-oxide-semiconductor field effect transistor (MOSFET) device used, for example, in giga-bit dynamic random access memories (DRAMs) are short channel effect and hot carrier reliability problems. To solve these problem, some process techniques such as ultrashallow junction and ultra-thin gate oxide are used. For example, a device design window of process conditions such as oxide thickness, punch-through doses, and lightly-doped drain (LDD) doses is disclosed in Hyunsang Hwang et al., "Performance and Reliability Optimization of Ultra Short Channel CMOS Device for Giga-bit DRAM Applications," IEEE IEDM Tech. Dig., pages 435-438 (1995) which is hereby incorporated by reference.
However, it becomes difficult to define a gate length below 0.1 μm due to some practical limitations, such as the resolution, under current optical photolithography technique. In order to circumscribe this situation, a resistor-thinning process based on an isotropic plasma resist ashing technique is applied in forming short channel MOSFETs with the gate length below 0.1 μm as disclosed in Mizuki Ono et al., "Sub-50 nm Gate Length N-MOSFETs with 10 nm Phosphorus Source and Drain Junctions," IEEE IEDM Tech. Dig., pages 119-122 (1993) which is also hereby incorporated by reference.
When the MOSFET devices are operated at a low supply voltage, the parasitic resistance effect due to the lightly-doped drain (LDD) structure should be reduced to maintain their performance. Further, the peak field location under the gate should be properly controlled, so that the hot carrier effect germane to the LDD structure can be improved. An inverse-T lightly-doped drain (ITLDD) transistor structure is disclosed in Tiao-Yuan Huang et al., "A New LDD Transistor with Inverse-T Gate Structure," IEEE Electronic Device Letters, VOL. EDL-8. No. 4, pages 151-153 (1987) which is hereby incorporated by reference. Although this ITLDD structure can alleviate hot carrier effect, its process is still not suitable for high-density or high-speed circuit application, in which fabrication of ultra-short channel devices with gate length less than 0.1 μm is required.
SUMMARY OF THE INVENTION
In accordance with the present invention, an ultra-short channel MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure is provided. In one embodiment, the present invention includes a semiconductor substrate, which includes a top surface; and a source region formed in the semiconductor substrate. Further, a drain region is formed in the semiconductor substrate spaced from the source region by a channel region. The drain region comprises a first doped portion adjacent the channel region and abutting to the top surface of the semiconductor substrate; and a second doped portion spaced from the channel region by the first doped portion and abutting to the top surface of the semiconductor substrate. Also, the present invention includes a first silicon oxide layer formed on the semiconductor substrate, the first silicon oxide layer being disposed over the channel region; and an inverse-T shaped silicon region formed on the first silicon oxide layer, wherein the inverse-T shaped silicon region is approximately disposed within the area of the first silicon oxide layer. A second silicon oxide sidewall insulating region abutting to a sidewall of the inverse-T shaped silicon region is provided, and a first silicide region is formed on the top surface of the inverse-T shaped silicon region. Finally, a second silicide region is formed on the top surface of the source region, and a third silicide region is formed on the top surface of the drain region.
BRIEF DESCRIPTION OF THE DRAWINGS
The foregoing aspects and many of the attendant advantages of this invention will become more readily appreciated as the same becomes better understood by reference to the following detailed description, when taken in conjunction with the accompanying drawings, wherein:
FIGS. 1-11 show cross-sectional views illustrative of various stages in the fabrication of an ultra-short channel MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure in accordance with the present invention.
DESCRIPTION OF THE PREFERRED EMBODIMENT
FIG. 1 shows a cross-sectional view illustrative of a portion of a semiconductor substrate 10 having field oxide regions 11 thereon in accordance with one embodiment of the present invention, wherein a thin gate oxide layer 12 having thickness of about 15-150 angstroms is grown on the substrate 10, for example, in a conventional thermal furnace. Next, a polysilicon layer 14, such as an undoped polysilicon layer, amorphous silicon layer or stacked silicon layers, is deposited on the gate oxide layer 12, and is used for forming a portion of a gate structure, which will become clear after the embodiment is described in details. In this embodiment, this polysilicon layer 14 is preferably deposited using a conventional low pressure chemical vapor deposition (LPCVD). The thickness of this polysilicon layer 14 can range from about 1000 to 3000 angstroms.
Still referring to FIG. 1, a dielectric cap layer 16, such as a silicon nitride layer, is formed over the polysilicon layer 14 to a thickness of about 100 to 1000 angstroms. In this embodiment, the silicon nitride layer 16 is deposited using a conventional low pressure chemical vapor deposition (LPCVD) or plasma enhanced chemical vapor deposition (PECVD). A sacrificial semiconductor layer 18 is formed on the silicon nitride layer 16. In this embodiment, n+ doped polysilicon is preferably chosen as the material of this sacrificial layer 18, and is deposited using a standard chemical vapor deposition process to a thickness of about 500-3000 angstroms.
A photoresist layer 20 is then formed and patterned on the doped polysilicon layer 18 using conventional photolithography techniques, thereby defining a gate region in the doped polysilicon layer 18 after the doped polysilicon layer 18 is etched back as shown in FIG. 2.
The patterned doped polysilicon layer 18 is then subjected to, for example, a low temperature (about 700-950° C.) steam oxidation process to oxidize the doped polysilicon layer 18, forming thermal polyoxide layer 22 into the doped polysilicon layer 18 along the sidewalls and top surface of the doped polysilicon layer 18 as shown in FIG. 3.
Using the thermal polyoxide layer 22 as a mask, the silicon nitride layer 16 is etched, and the undoped polysilicon layer 14 is partially etched, forming a cross section as shown in FIG. 4.
The thermal polyoxide layer 22 is then removed, for example, by diluted hydrofluoric (HF) solution or buffered oxide etch (BOE), wherein the remained undoped polysilicon layer 14 is used to protect the field oxide regions 11 and the gate oxide layer 12 from being effected. Subsequently, the silicon nitride layer 16 is etched using the doped polysilicon layer 18 as a mask, resulting in the cross section shown in FIG. 5. The formed silicon nitride layer 16 is further used as a mask to etch the undoped polysilicon layer 14, resulting in an inverse-T gate structure as shown in FIG. 6. The substrate 10 is then subjected to an ion implantation through the inverse-T gate structure, forming source/drain region 9 having a lightly-doped drain profile in the substrate 10 as shown in FIG. 7.
Referring to FIG. 8, a spacer 24 is formed on the sidewalls of the silicon nitride layer 16, the undoped polysilicon layer 14, and the gate oxide layer 12. In this embodiment, silicon oxide is chosen as the material of the spacer 24. This oxide spacer 24 is preferably formed by firstly blanket depositing a silicon oxide layer 24 by a chemical vapor deposition (CVD) over the structure of FIG. 7, followed by etching back this silicon oxide layer 24.
In FIG. 9, after the silicon nitride layer 16 is removed, a metal layer 26, such as Ti, Co, Pt, Ni, Cr, W, or Pd, is deposited over the exposed substrate 10, the spacer 24, and the undoped polysilicon layer 14 by sputtering or chemical vapor deposition (CVD).
Referring to FIG. 10, the gate region in the undoped polysilicon layer 14, and the source/drain region 9 in the substrate 10 are then doped by a high dose (about 1014 -1016 atoms/cm2) implant through the metal layer 26.
To complete the present invention, an annealing process is performed to form silicide regions 28 over the gate region 14 and source/drain region 9, therefore forming an ultra-short channel salicided MOSFET with an inverse-T gate lightly-doped drain (ITLDD) structure as shown in FIG. 11. In this embodiment, the annealing process is preferably a conventional two-step rapid thermal process (RTP). It is noted that the oxide spacer 24 previously formed in connection with FIG. 8 is used in the resultant MOSFET structure to prevent the silicide region 28 on the gate 14 from being electrically bridged to the silicide region 28 on the source/drain 9. It is appreciated that the term "ultra-short" in this specification is commonly used in semiconductor industry to refer to a channel width in the range of about 4-100 nm.
Although specific embodiments have been illustrated and described, it will be obvious to those skilled in the art that various modifications may be made without departing from the spirit which is intended to be limited solely by the appended claims.

Claims (10)

What is claimed is:
1. A semiconductor device with an inverse-T gate lightly-doped drain (ITLDD) structure, said device comprising:
a semiconductor substrate, including a top surface;
a source region formed in said semiconductor substrate;
a drain region formed in said semiconductor substrate spaced from said source region by a channel region;
an inverse-T shaped silicon region formed over said semiconductor substrate, said inverse-T shaped silicon region being approximately disposed within area of said channel region, said inverse-T shaped silicon region including a pair of sidewalls and two arms, each of said arms including a first surface and a second surface;
a sidewall insulating region abutting said sidewalls and said first and second surface of said arms of said inverse-T shaped silicon region;
a first conductive region formed on a top surface of said inverse-T shaped silicon region;
a second conductive region formed on a top surface of said source region; and
a third conductive region formed on a top surface of said drain region.
2. The device according to claim 1, wherein said inverse-T shaped silicon region comprises polysilicon.
3. The device according to claim 1, wherein said inverse-T shaped silicon region comprises amorphous silicon.
4. The device according to claim 1, wherein said drain region comprising:
a first doped portion adjacent said channel region and abutting to said top surface of said semiconductor substrate; and
a second doped portion spaced from said channel region by said first doped portion and abutting to said top surface of said semiconductor substrate.
5. The device according to claim 1, further comprising a silicon layer disposed between said semiconductor substrate and said inverse-T shaped silicon region.
6. The device according to claim 1, wherein said sidewall insulating region comprises silicon oxide.
7. The device according to claim 1, wherein said first conductive region, said second conductive region, and said third conductive region comprise silicide.
8. A semiconductor device with an inverse-T gate lightly-doped drain (ITLDD) structure, said device comprising:
a semiconductor substrate, including a top surface;
a source region formed in said semiconductor substrate;
a drain region formed in said semiconductor substrate spaced from said source region by a channel region, said drain region comprising:
a first doped portion adjacent said channel region and abutting to said top surface of said semiconductor substrate; and
a second doped portion spaced from said channel region by said first doped portion and abutting to said top surface of said semiconductor substrate;
a first silicon oxide layer formed on said semiconductor substrate, said first silicon oxide layer being disposed over said channel region;
an inverse-T shaped silicon region formed on said first silicone oxide layer, said inverse-T shaped silicon region being approximately disposed within area of said first silicon oxide layer, said inverse-T shaped silicon region including a pair of sidewalls and two arms, each of said arms including a first surface and a second surface;
a second silicon oxide sidewall insulating region abutting said sidewalls and said first and second surface of said arms of said inverse-T shaped silicon region;
a first silicide region formed on a top surface of said inverse-T shaped silicon region;
a second silicide region formed on a top surface of said source region; and
a third silicon region formed on a top surface of said drain region.
9. The device according to claim 8, wherein said inverse-T shaped silicon region comprises polysilicon.
10. The device according to claim 8, wherein said inverse-T shaped silicon region comprises amorphous silicon.
US09/050,669 1998-03-30 1998-03-30 Semiconductor device with an inverse-T gate lightly-doped drain structure Expired - Lifetime US5986305A (en)

Priority Applications (1)

Application Number Priority Date Filing Date Title
US09/050,669 US5986305A (en) 1998-03-30 1998-03-30 Semiconductor device with an inverse-T gate lightly-doped drain structure

Applications Claiming Priority (1)

Application Number Priority Date Filing Date Title
US09/050,669 US5986305A (en) 1998-03-30 1998-03-30 Semiconductor device with an inverse-T gate lightly-doped drain structure

Publications (1)

Publication Number Publication Date
US5986305A true US5986305A (en) 1999-11-16

Family

ID=21966666

Family Applications (1)

Application Number Title Priority Date Filing Date
US09/050,669 Expired - Lifetime US5986305A (en) 1998-03-30 1998-03-30 Semiconductor device with an inverse-T gate lightly-doped drain structure

Country Status (1)

Country Link
US (1) US5986305A (en)

Cited By (17)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20010041392A1 (en) * 2000-05-12 2001-11-15 Hideomi Suzawa Semiconductor device and manufacturing method thereof
US20010052950A1 (en) * 2000-03-27 2001-12-20 Shunpei Yamazaki Semiconductor display device and manufacturing method thereof
US20020006705A1 (en) * 2000-05-12 2002-01-17 Hideomi Suzawa Semiconductor device and method for manufacturing same
KR100349367B1 (en) * 1999-06-28 2002-08-21 주식회사 하이닉스반도체 Method of manufacturing semiconductor device
KR20030044340A (en) * 2001-11-29 2003-06-09 주식회사 하이닉스반도체 Method of forming a transistor in a semiconductor device
US20030232475A1 (en) * 2002-06-14 2003-12-18 Katsuhito Sasaki Method of fabricating LDMOS semiconductor devices
US6674139B2 (en) * 2001-07-20 2004-01-06 International Business Machines Corporation Inverse T-gate structure using damascene processing
US6730552B1 (en) 2003-06-26 2004-05-04 International Business Machines Corporation MOSFET with decoupled halo before extension
US6759678B2 (en) 2000-03-06 2004-07-06 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device
US20050062161A1 (en) * 2003-09-22 2005-03-24 International Business Machines Corporation Conductor line structure and method for improved borderless contact process tolerance
US20050186744A1 (en) * 2004-02-24 2005-08-25 International Business Machines Corporation MOSFET with decoupled halo before extension
US20060078613A1 (en) * 2000-04-26 2006-04-13 Sanders Steven W Compositions and methods for minimizing adverse drug experiences associated with oxybutynin therapy
US20070148887A1 (en) * 2005-12-28 2007-06-28 Dae Kyeun Kim Method for manufacturing semiconductor device
WO2013019334A1 (en) * 2011-08-03 2013-02-07 Cree, Inc. Forming sic mosfets with high channel mobility by treating the oxide interface with cesium ions
US8685817B1 (en) 2012-11-19 2014-04-01 International Business Machines Corporation Metal gate structures for CMOS transistor devices having reduced parasitic capacitance
US10437241B2 (en) 2016-12-16 2019-10-08 General Electric Company Systems and methods for generating maintenance packages
US11270886B2 (en) * 2017-07-21 2022-03-08 Stmicroelectronics (Rousset) Sas Transistor comprising a lengthened gate

Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5182619A (en) * 1991-09-03 1993-01-26 Motorola, Inc. Semiconductor device having an MOS transistor with overlapped and elevated source and drain
US5210435A (en) * 1990-10-12 1993-05-11 Motorola, Inc. ITLDD transistor having a variable work function
US5241203A (en) * 1991-07-10 1993-08-31 International Business Machines Corporation Inverse T-gate FET transistor with lightly doped source and drain region
US5304504A (en) * 1991-12-18 1994-04-19 Sgs-Thomson Microelectronics, Inc. Method of forming a gate overlap LDD structure
US5739573A (en) * 1994-07-22 1998-04-14 Nec Corporation Semiconductor device with improved salicide structure and a method of manufacturing the same

Patent Citations (5)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US5210435A (en) * 1990-10-12 1993-05-11 Motorola, Inc. ITLDD transistor having a variable work function
US5241203A (en) * 1991-07-10 1993-08-31 International Business Machines Corporation Inverse T-gate FET transistor with lightly doped source and drain region
US5182619A (en) * 1991-09-03 1993-01-26 Motorola, Inc. Semiconductor device having an MOS transistor with overlapped and elevated source and drain
US5304504A (en) * 1991-12-18 1994-04-19 Sgs-Thomson Microelectronics, Inc. Method of forming a gate overlap LDD structure
US5739573A (en) * 1994-07-22 1998-04-14 Nec Corporation Semiconductor device with improved salicide structure and a method of manufacturing the same

Non-Patent Citations (6)

* Cited by examiner, † Cited by third party
Title
Hyunsang Hwang et al., Performance and Reliability Optimization of Ultra Short Channel CMOS Device for Giga bit DRAM Applications, 1995 IEEE, pp. 435 438. *
Hyunsang Hwang et al., Performance and Reliability Optimization of Ultra Short Channel CMOS Device for Giga-bit DRAM Applications, 1995 IEEE, pp. 435-438.
Mizuki Ono et al., Sub 50 NM Gate Length N Mosfets with 10 NM Phosphorus Source and Drain Junctions, 1993 IEEE, pp. 119 122. *
Mizuki Ono et al., Sub-50 NM Gate Length N-Mosfets with 10 NM Phosphorus Source and Drain Junctions, 1993 IEEE, pp. 119-122.
Tiao Yuan Huang et al., A New LDD Transistor with Inverse T Gate Structure, IEEE Electron Device Letters, vol. EDL 8, No. 4, Apr. 1987, pp. 151 153. *
Tiao-Yuan Huang et al., A New LDD Transistor with Inverse-T Gate Structure, IEEE Electron Device Letters, vol. EDL-8, No. 4, Apr. 1987, pp. 151-153.

Cited By (46)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
KR100349367B1 (en) * 1999-06-28 2002-08-21 주식회사 하이닉스반도체 Method of manufacturing semiconductor device
US20040206974A1 (en) * 2000-03-06 2004-10-21 Semiconductor Energy Laboratory, Co., Ltd. . Semiconductor device and manufacturing method thereof
US9601515B2 (en) 2000-03-06 2017-03-21 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US8772778B2 (en) 2000-03-06 2014-07-08 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US8124973B2 (en) 2000-03-06 2012-02-28 Semiconductor Energy Laboratory Co., Ltd. Electronic appliance including transistor having LDD region
US6759678B2 (en) 2000-03-06 2004-07-06 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device
US7112817B2 (en) 2000-03-06 2006-09-26 Semiconductor Energy Laboratory Co., Ltd. Electronic appliance including transistor having LDD region
US20010052950A1 (en) * 2000-03-27 2001-12-20 Shunpei Yamazaki Semiconductor display device and manufacturing method thereof
US7486344B2 (en) 2000-03-27 2009-02-03 Semiconductor Energy Laboratory Co., Ltd. Semiconductor display device and manufacturing method thereof
US20070138480A1 (en) * 2000-03-27 2007-06-21 Semiconductor Energy Laboratory Co., Ltd. Semiconductor display device and manufacturing method thereof
US7218361B2 (en) 2000-03-27 2007-05-15 Semiconductor Energy Laboratory Co., Ltd. Semiconductor display device and manufacturing method thereof
US20060078613A1 (en) * 2000-04-26 2006-04-13 Sanders Steven W Compositions and methods for minimizing adverse drug experiences associated with oxybutynin therapy
US6773996B2 (en) 2000-05-12 2004-08-10 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing same
US20070272989A1 (en) * 2000-05-12 2007-11-29 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing the same
US7589382B2 (en) 2000-05-12 2009-09-15 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing the same
US6809339B2 (en) 2000-05-12 2004-10-26 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and method for manufacturing same
US20050040403A1 (en) * 2000-05-12 2005-02-24 Semiconductor Energy Laboratory Co., Ltd., A Japan Corporation Semiconductor device and method for manufacturing same
US20020006705A1 (en) * 2000-05-12 2002-01-17 Hideomi Suzawa Semiconductor device and method for manufacturing same
SG112805A1 (en) * 2000-05-12 2005-07-28 Semiconductor Energy Lab Semiconductor device and manufacturing method thereof
US8470647B2 (en) 2000-05-12 2013-06-25 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US20040195590A1 (en) * 2000-05-12 2004-10-07 Semiconductor Energy Laboratory Co., Ltd., A Japan Corporation Semiconductor device and manufacturing method thereof
US7224028B2 (en) 2000-05-12 2007-05-29 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device that includes a gate insulating layer with three different thicknesses
US20010041392A1 (en) * 2000-05-12 2001-11-15 Hideomi Suzawa Semiconductor device and manufacturing method thereof
US20040135216A1 (en) * 2000-05-12 2004-07-15 Semiconductor Energy Laboratory Co. Ltd., A Japan Corporation Semiconductor device and method for manufacturing same
US7151015B2 (en) 2000-05-12 2006-12-19 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US7161177B2 (en) 2000-05-12 2007-01-09 Semiconductor Energy Laboratory Co., Ltd. Semiconductor device and manufacturing method thereof
US20040097041A1 (en) * 2001-07-20 2004-05-20 International Business Machines Corporation Inverse-T gate structure using damascene processing
US7026202B2 (en) 2001-07-20 2006-04-11 International Business Machines Corporation Inverse-T gate structure using damascene processing
US6674139B2 (en) * 2001-07-20 2004-01-06 International Business Machines Corporation Inverse T-gate structure using damascene processing
KR20030044340A (en) * 2001-11-29 2003-06-09 주식회사 하이닉스반도체 Method of forming a transistor in a semiconductor device
US6800528B2 (en) * 2002-06-14 2004-10-05 Oki Electric Industry Co., Ltd. Method of fabricating LDMOS semiconductor devices
US20030232475A1 (en) * 2002-06-14 2003-12-18 Katsuhito Sasaki Method of fabricating LDMOS semiconductor devices
US6730552B1 (en) 2003-06-26 2004-05-04 International Business Machines Corporation MOSFET with decoupled halo before extension
US7005744B2 (en) * 2003-09-22 2006-02-28 International Business Machines Corporation Conductor line stack having a top portion of a second layer that is smaller than the bottom portion
US20050062161A1 (en) * 2003-09-22 2005-03-24 International Business Machines Corporation Conductor line structure and method for improved borderless contact process tolerance
US7253066B2 (en) 2004-02-24 2007-08-07 International Business Machines Corporation MOSFET with decoupled halo before extension
US20050186744A1 (en) * 2004-02-24 2005-08-25 International Business Machines Corporation MOSFET with decoupled halo before extension
US20070148887A1 (en) * 2005-12-28 2007-06-28 Dae Kyeun Kim Method for manufacturing semiconductor device
US7524714B2 (en) * 2005-12-28 2009-04-28 Dongbu Hitek Co., Ltd. Method for manufacturing semiconductor device
US20130034941A1 (en) * 2011-08-03 2013-02-07 Sarit Dhar Forming sic mosfets with high channel mobility by treating the oxide interface with cesium ions
WO2013019334A1 (en) * 2011-08-03 2013-02-07 Cree, Inc. Forming sic mosfets with high channel mobility by treating the oxide interface with cesium ions
US9984894B2 (en) * 2011-08-03 2018-05-29 Cree, Inc. Forming SiC MOSFETs with high channel mobility by treating the oxide interface with cesium ions
US8685817B1 (en) 2012-11-19 2014-04-01 International Business Machines Corporation Metal gate structures for CMOS transistor devices having reduced parasitic capacitance
US8815669B2 (en) 2012-11-19 2014-08-26 International Business Machines Corporation Metal gate structures for CMOS transistor devices having reduced parasitic capacitance
US10437241B2 (en) 2016-12-16 2019-10-08 General Electric Company Systems and methods for generating maintenance packages
US11270886B2 (en) * 2017-07-21 2022-03-08 Stmicroelectronics (Rousset) Sas Transistor comprising a lengthened gate

Similar Documents

Publication Publication Date Title
US5837588A (en) Method for forming a semiconductor device with an inverse-T gate lightly-doped drain structure
US5834353A (en) Method of making deep sub-micron meter MOSFET with a high permitivity gate dielectric
US5986305A (en) Semiconductor device with an inverse-T gate lightly-doped drain structure
US6087234A (en) Method of forming a self-aligned silicide MOSFET with an extended ultra-shallow S/D junction
US6136636A (en) Method of manufacturing deep sub-micron CMOS transistors
US6967143B2 (en) Semiconductor fabrication process with asymmetrical conductive spacers
US5637903A (en) Depleted gate transistor for high voltage operation
US5702972A (en) Method of fabricating MOSFET devices
JPH045265B2 (en)
JPH081957B2 (en) Method for manufacturing semiconductor device
US5460998A (en) Integrated P+ implant sequence in DPDM process for suppression of GIDL
KR20020003028A (en) Method for making an soi metal oxide fet
US6165857A (en) Method for forming a transistor with selective epitaxial growth film
US5134452A (en) MIS type FET semiconductor device with gate insulating layer having a high dielectric breakdown strength
US6566208B2 (en) Method to form elevated source/drain using poly spacer
US5972761A (en) Method of making MOS transistors with a gate-side air-gap structure and an extension ultra-shallow S/D junction
KR20040029119A (en) Improved high k-dielectrics using nickel silicide
US6200840B1 (en) Method for producing PMOS devices
US6649308B1 (en) Ultra-short channel NMOSFETS with self-aligned silicide contact
US5915181A (en) Method for forming a deep submicron MOSFET device using a silicidation process
US6969646B2 (en) Method of activating polysilicon gate structure dopants after offset spacer deposition
US6117712A (en) Method of forming ultra-short channel and elevated S/D MOSFETS with a metal gate on SOI substrate
US6258682B1 (en) Method of making ultra shallow junction MOSFET
US6069044A (en) Process to fabricate ultra-short channel nMOSFETS with self-aligned silicide contact
JP2796249B2 (en) Method for manufacturing semiconductor memory device

Legal Events

Date Code Title Description
AS Assignment

Owner name: TEXAS INSTRUMENTS-ACER INCORPORATED, TAIWAN

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:WU, SHYE-LIN;REEL/FRAME:009082/0411

Effective date: 19980316

STCF Information on status: patent grant

Free format text: PATENTED CASE

AS Assignment

Owner name: TSMC-ACER SEMICONDUCTOR MANUFACTURING CORPORATION,

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:ACER SEMICONDUCTOR MANUFACTURING INC.;REEL/FRAME:011087/0473

Effective date: 20000630

Owner name: TAIWAN SEMICONDUCTOR MANUFACTURING CO., LTD., TAIW

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNOR:TSMC-ACER SEMICONDUCTOR MANUFACTURING CORPORATION;REEL/FRAME:011122/0153

Effective date: 20000630

FPAY Fee payment

Year of fee payment: 4

FPAY Fee payment

Year of fee payment: 8

FPAY Fee payment

Year of fee payment: 12